Hobart and Miller are different companies and the machines are manufactured in different facilities (Miller in Wisconsin and Hobart in Ohio, I think). However, both companies are owned by Illinois Tool Works, so there is some integration of parts and components.
Both Miller and Hobart make great welders. I had a HH 140 and was never disappointed with it. Now I have a Miller 211, and I like it too.
I just put in about $600 for a 140 mig and a tank. It is a piece of ****. I've had another Hobart before and this one has the same problem. The wires always get tangled or stuck in the tensioner. I'm not seeing the difference between a regular gas and gas.